CVE-2016-8657 in Red Hat
Summary
by MITRE
It was discovered that EAP packages in certain versions of Red Hat Enterprise Linux use incorrect permissions for /etc/sysconfig/jbossas configuration files. The file is writable to jboss group (root:jboss, 664). On systems using classic /etc/init.d init scripts (i.e. on Red Hat Enterprise Linux 6 and earlier), the file is sourced by the jboss init script and its content executed with root privileges when jboss service is started, stopped, or restarted.
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Analysis
by VulDB Data Team • 04/27/2023
The vulnerability described in CVE-2016-8657 represents a critical privilege escalation flaw within the Red Hat Enterprise Linux EAP package configuration management system. This issue affects systems running Red Hat Enterprise Linux 6 and earlier versions where the traditional /etc/init.d init script system is employed. The core problem lies in the improper file permission settings applied to the /etc/sysconfig/jbossas configuration file, which creates an exploitable condition that allows unauthorized users to gain elevated privileges.
The technical flaw manifests through the incorrect file permissions of 664, which grants read and write access to both the root user and the jboss group. This misconfiguration becomes particularly dangerous because the /etc/sysconfig/jbossas file is explicitly sourced and executed by the jboss init script during service lifecycle operations including start, stop, and restart commands. When the init script executes with root privileges, any modifications made to this configuration file by members of the jboss group can be leveraged to inject malicious code that will subsequently run with elevated privileges. This creates a direct path for privilege escalation attacks where attackers can manipulate system behavior through configuration file modifications.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of the system. Attackers who gain membership to the jboss group can effectively compromise the entire system by modifying the configuration file to execute arbitrary commands with root privileges. This affects not only the jboss application server itself but potentially the entire system integrity since the executed commands run with the highest available privileges. The vulnerability is particularly concerning in multi-user environments where the jboss group may contain users who should not have such elevated access rights, creating a significant attack surface that can be exploited for persistent system compromise.
Security mitigations for this vulnerability should focus on immediate permission correction and system hardening measures. The primary fix involves changing the file permissions of /etc/sysconfig/jbossas to restrict write access to the root user only, typically implementing permissions of 644 or stricter. Additionally, system administrators should audit group memberships to ensure that only authorized personnel have access to the jboss group. This vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a classic example of privilege escalation through insecure file handling. From an ATT&CK framework perspective, this maps to privilege escalation techniques where adversaries leverage weak file permissions to gain elevated system access, specifically falling under the category of "Modify System Execution" and "Exploitation for Privilege Escalation" tactics. Organizations should also implement regular security audits and configuration management processes to prevent similar issues in the future, ensuring that all system configuration files maintain appropriate access controls and that service initialization processes do not execute untrusted configuration data with elevated privileges.